The main water controls should be in your basement or outside the house. If you can find a dedicated shut off valve for the shower (usually behind a panel on the other side of the wall), you can turn the water off there instead. However, this is not easily accessible in all homes.
Wrap the wrench teeth with duct tape to prevent damaging the finish on the shower head.
If the washer or O-ring is worn out, go to the hardware store and buy a new one.
Wrap a thin layer of teflon tape around the exposed threads at the end of the pipe. Turn the pipe clockwise to screw it back into the wall.
Other faucets have two handles (one each for hot and cold water), or work as a lever rather than turning left and right. These use either ball valves or ceramic disks and are more complicated to repair. Contact a plumber for assistance.
Cover the shower drain with a rag to keep screws from accidentally slipping down it.
The cartridge may have a hex screw instead. If so, use a hex wrench to loosen it. The handle may stick a little bit. If so, try blowing on it with a hairdryer for a few minutes, then try again to pull it off. If that still doesn’t work, go to your local hardware store and ask for a device called a “handle puller” which will give you additional leverage to pull the handle off.
If the cartridge is stuck and won’t come out, Use the cartridge puller. This slides over the end of the cartridge and gives you additional leverage to twist it out.
Pull the escutcheon off of the wall when you’re done. Gently pry at it with a flathead screwdriver if it seems stuck.
Silicone caulk is waterproof and widely available. It’s the best option for sealing showers. Look for a variety specially marked for kitchens or baths, if possible.
Scrapping over the caulk with a popsicle stick and wiping it with a wet rag just helps make a smooth, even surface. For a simpler fix, you can go over the caulk with a wet finger instead.
